Circuit interrupter protective device

ABSTRACT

A circuit interrupter protective device responsive to abnormal currents in conductors of an electrical distribution system characterized by a circuit breaker within a first insulating housing and having a mechanism for opening and closing separable contacts which mechanism comprises a releasable member movable from latched to unlatched positions, trip means comprising a stationary magnetic structure for each conductor as well as a coil and core assembly and armature therefor, a trip bar movable to unlatch the circuit breaker mechanism and biased in the latched position, lever means associated with the stationary magnetic structure for moving the trip bar to the unlatched position, the lever means comprising the armature and being movable in response to abnormal currents in at least one of the conductors, the lever means being biased away from the core assembly, and means for adjusting the spacing between the lever and core assembly.

United States Patent [191 Maier et al. 1 June 4, 1974 CIRCUITINTERRUPTER PROTECTIVE DEVICE [57] ABSTRACT [75] Inv t Alf d E, M iBeaver F ll A circuit interrupter protective device responsive to WilliSt h J Beaver, abnormal currents in conductors of an electrical distribh f P bution system characterized by a circuit breaker within a firstinsulating housing and having a mecha- [73 Asslgnee: Westmghouse ElecmcCm'porauon nism for opening and closing separable contacts whichp'ttsburgh mechanism comprises a releasable member movable [22] Fil d; M27, 1973 from latched to unlatched positions, trip means comprising astationary magnetic structure for each con- [211 App]' 345394 ductor aswell as a coil and core assembly and armature therefor, a trip barmovable to unlatch the circuit [52] US. Cl. 335/176, 335/42 breakermechanism and biased in the latched position, [51] Int. Cl. H0111 71/74lever means ssoc a ed with the stationary magnetic [58] Field of Search335/42, 176 Structure o o g the trip bar to the unlatched position, thelever means comprising the armature and [56] References Cit d beingmovable in response to abnormal currents in at UNITED STATES PATENTSleast one of the conductors, the lever means being bi- I 3 I 76 asedaway from the core assembly, and means for ad- 3,593,234 7/l97lCharbonneau et a1. 35/ justing the p g between the lever and core assemPrimary Examiner-Harold Broome Attorney, Agent, or F irmL. P. Johns 9Claims, 8 Drawing Flgures lOl H9 83k) l N3 O [b.lll l 09 I23 I07 j r beI05 |2| 69 SHEET 10F 4 PATENTEBJIIII 4 m4 SHEET 2 0F 4 FIGB PATENTEDM 4m4 FIG.6

CIRCUIT INTERRUPTER PROTECTIVE DEVICE CROSS-REFERENCE TO RELATEDAPPLICATIONS This invention is related to that disclosed in theapplication of Albert E. Mainer and William I. Stephenson, Jr., Ser. No.345,395, filed March 27, 1973.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionpertains to a protective device for a circuit interrrupter and moreparticularly it pertains to a monitoring means within an insulatinghousing which in turn is contained within the outer housing of thecircuit interrupter.

2. Description of the Prior Art Generally, circuit breakers thatcomprise overcurrent protective devices have external mounting means forsuch devices on the circuit breaker housing such as disclosed in US.Pat. No. 3,530,414. Circuit breakers of that type have-functionedsatisfactorily for responding to such abnormal currents as overcurrents,ground fault currents, and short circuits that occur in an electricaldistribution system.

SUMMARY OF THE INVENTION In accordance with this invention, a protectivedevice for a circuit interrupter is provided which device comprises astationary magnetic structure for each'conductor of an electricaldistribution system and comprising a coil and core assembly and anarmature, a trip bar movable to effect tripping of the circuit breakermechanism and being biased in the latched position, the lever meansassociated with each stationary magnetic structure for moving the tripbar to the unlatched position, the lever means comprising the armatureand being movable in response to abnormal currents in at least one ofthe conductors, the lever means comprising a lever which is biased awayfrom the core assembly,

and means for adjusting the spacing between the lever and the coreassembly.

The advantage of the device of this invention is that it provides for amore compact tripping unit as well as a more efficient unit. I

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a vertical sectional view ofa multi-pole circuit breaker; FIG. 2 is a vertical sectional view takenon the line 11-" of FIG. 1;

FIG. 3 is a vertical sectional view taken on the line IIIIII of FIG. 1;

FIG. 4 is a vertical sectional view taken on the line IV-IV of FIG. 3;

FIG. 5 is a vertical sectional view taken" on the line V-V of FIG. 3;

FIG. 6 is a plan view of the trip device shown in FIGS.

FIG. 7 is a vertical sectional view of another embodiment of theinvention; and

FIG. 8 is a vertical sectional view taken on the line VlIlVlll of FIG.7.

DESCRIPTION-OF THE PREFERRED EMBODIMENTS breaker mechanism 7 supportedwithin the housing. The housing 5 comprises an insulating base 9 and aninsulating cover 11.

The circuit breaker mechanism 7 comprises an operating mechanism 13, anda latch and trip device 15. Except for the latch and trip device. thecircuit breaker 3 is of the type that is generally described in thepatent to Albert R. Cellerini et al, US. Pat. No. 3,287,534, issuedNovember 22, I966. The circuit breaker 3 is a threepole circuit breakercomprising three compartments disposed in side-by-side relationships.The center pole compartment (FIG. I) is separated from the two outerpole compartments by insulating barrier walls formed with the housingbase 9 and cover 11. The operating mechanism 13 is disposed in thecenter pole compartment and is a single operating mechanism foroperating the contacts of all three pole units.

Each pole unit comprises a stationary contact 21 that is fixedly securedto a rigid main conductor 23 that in turn is secured to the base 9 bybolt 25. In each pole unit, a movable contact 27 is welded or brazed toa contact arm 29 that is mounted on a switch arm 31 by a pivot pin 33.The arms 29 and 31 for all three of the pole units are supported at oneend thereof and rigidly connected on a common insulating tie bar 35 bywhich the arms of all three pole units move in unison. Each of thecontact arms 29 is biased about the associated pivot pin 33 by means ofa spring 37 to provide contact pressure in the closed position.

The operating mechanism 13 actuates the switch arms 31 between open andclosed positions. The mechanism comprises a pivoted formed operatinglever 39, a toggle comprising two toggle links 41 and 43, overcentersprings 45 and 47, and a pivoted releasable cradle or arm 49 controlledby the trip device 15. An insulating shield 51 for substantially closingan opening 53 in the cover 11, is mounted onthe outer end of theoperating lever 39, and has an integral handle portion 55 extending outthrough the opening to enable manual operation of the breaker. Thetoggle links 41 and 43 are pivotally connected together by a knee pivotpin 57. The toggle link 41 is pivotally connected to the releasable arm49 by a pin 59, and the'toggle link 43 is pivotally connected to theswitch arm 31 of the center pole unit by a pin 61. The overcentersprings 45 and 47 are connected under tension between the knee pivot pin57 and the outer end of the operating lever 39. The circuit breaker ismanually operated to the open position by movement of the handle portion55 in a counterclockwise direction to the off position, which movementactuates the overcenter springs 45, 47 to collapse the toggle links 41and 43 to the position shown in FIG. I, and opening movement of thecontact arm 29 for all of the pole units in a manner well known in theart.

The circuit breaker is manually closed by reverse movement of the handleportion 55 from the *otf" position to the on position, which movementcauses the springs 45,47 to move overcenter and straighten the togglelinks 41, 43 thereby moving the contact arm 29, for all of the poleunits, to the closed position as shown in broken line position.

The trip device 15 serves to effect automatic release of the releasablecradle or arm 49 and opening of the breaker contacts for all of the poleunits, in response to predetermined overload conditions in the circuitbreaker through any or all pole units of the circuit breaker in a mannerdescribed hereinbelow.

The circuit through each pole unit extends from a right-hand terminal 63through the conductor 23, the contacts 21, 27, the contact arm 29, aflexible conductor 65, that is secured to the contact arm 29, aconductor 67, a trip conductor 69, to a left-hand terminal connector 71.Bolt means 73 secure one end of the trip conductor 69 to the conductor67 and the other end of the trip conductor 69 is disposed between abackup plate 75 and the terminal 71 where it is secured in place bymounting bolt 77 of the terminal 71.

As shown in FIGS. 2-6 the latch and trip device comprises a moldedinsulating housing base 81 and a molded insulating housing cover 79secured to the base to enclose a molded insulating trip bar 83 that iscommon to all three of the pole units. As shown in FIG. 3, the base 81includes a pair of spaced partitions 85 and 87 which are verticallydisposed and integral with the base for separating the interior of thehousing into three compartments, each compartment containing one of thethree poles. in a similar manner, the cover 79 is provided withpartitions corresponding to partitions 85 and 87 and have matingsurface'therewith in a manner similar to the mating surfaces of theperipheral surfaces of the base 81 and cover 79 as indicated by aparting line 89 (FIG. 6).

As shown in FIG. 3, the partitions 85 and 87 have notches 91 and 93,respectively, which together with flat surfaces of the cover 79 serve asjournals for round shaft portions 95 and 97 of the trip bar 83.Accordingly, when the-housing base 8land cover 79 are assembled' theyretain the trip bar 83 in place whereby the trip bar is free to rotateon an axis extending through the shaft portions 95 and 97. As shown moreparticularly, in FIG. 5, each section of the trip bar 83 located withinthe space compartments of the housing comprise upper and lower portions83a and 83b, which are above and below the axis of rotation of the tripbar. Each upper portion 83a is provided with an adjusting screw and nutassembly 99 which cooperates with a bimetal member 101 for adjusting thespacing between the upper ends of the bimetal member and the trip barportion 830 in response to the degree of deflection of the upper end ofthe member 101 toward the member 83d, whereby the trip bar 83 is rotatedclockwise bythe bimetal member and thereby trips the circuit breaker tothe open position. The lower end portion 83b ofthe trip bar 83 ispreferably provided with a drwve screw 103 by which contact is made withan adjoining member for similar rotation of the trip bar in the mannerto be described hereinbelow.

As shown more particularly in FIG. 5, the trip conductor 69 includes aninverted U-shaped intermediate portion 69a which constitutes a singleloop of a stationary magnetic structure. Stationary magnetic structurealso comprises a magnetic core 105, a U-shaped frame 107 having a pairof spaced flanges 109 one of which is shown in FIG. 5, and an armature111. The assembly of the intermediate U-shaped portion 69a, the core105, and the intermediate portion of the frame 107 together with thelower portion of the bimetal member 101 are secured in place by suitablemeans such as rivets 113 on the housing base 79. The'lowe'r end portionof the bimetal member 101 is in surface to surface contact withthe'conducot 69 whereby upon the occurrence of a low persistent overloadcurrent below a predetermined value of, for example, ten times normalrated current, the bimetal member 101 is heated and deflects to theright through an air gap dependent upon the setting of the'adjustmentscrew 99. Thus, when a low persistent overload current occurs, the tripbar 83 is actuated to trip the circuit breaker.

The armature 111 is disposed between the space flanges 109 of theU-shaped frame 107 and is pivotally mounted therein to rotate about anaxis 115 near the lower end of the armature. For that purpose, thearmature 111 is preferably mounted by suitable means such as rivets 117on a support lever 119 having oppositely extending out-turned lugs 121which are seated in corresponding openings 123 in the flanges 109. Eachflange 109 is also provided with a V-shaped notch 125 into which edgeportions of the lever 119 and armature 111 extend. The notches 125thereby limit movement of the assembly of the lever 119 and armature 111when the armature is attracted toward the core 105. Accordingly, theassembly of the lever 119 and armature 111 which is biased in theclockwise direction by coil springs 127 (FIG. 3) is movablecounterclockwsie against the springs to engage the drive screw '103 andthereby rotates the trip bar 83 clockwise. When an overload currentabove a value such, for example, as ten times normal rated current or ashrot circuit current occurs, the stationary magnetic structure isenergized and the armature 111 is attracted toward the core 105 causinginstantaneous release of the releasable arm 49 and opening of thecontacts 21 and 27.

In addition to the foregoing, means are provided for adjusting thespacing between the armature 111 and the core 105, whereby upon maximumspacing of the armature from the core, a greater current overload isrequired to attract the armature toward the core. Conversely, when thespacing is reduced, a smaller overload current is required to actuatethe trip bar 83. For that purpose a trip lever 129 having a lower enddisposed over the upper end of the lever 119 is mounted within thehousing and is provided with calibration means including a calibrationscrew 131 at the upper end of the lever 129. As shown in FIG. 3, eachlever 129 includes a notch 133 on each opposite side thereof which notchis seated in corresponding projections 135 of the housing base 79 wherethe levers 129 are retained in place by thecover 81. An adjusting knob137 is seated within the top end of the housing base and is providedwith a lower end portion having a cam surface. lnasmuch as the lever 129is biased counterclockwise about its pivot point by the springs 127 ofthe lower lever 119 the calibration screw 131 rides on the cam surfaceof a lower portion 139 of the adjusting knob 137.

As shown in FIGS. 3 and 5, each adjusting knob 137 includes a flange141, the lower surface of which includes spaced notches 143. An indexmember is disposed below the flange 143 and is provided with aprojection 147 for engaging one of the spaced notches 143 as thecalibrating screw 137 is rotated to the desired position. Accordingly,the desired spacing between the armature 111 and the core 105 isestablished by rotation of the adjusting knob 137.

Since the housing cover 79 is used to hold the levers 129 in place, itis necessary to assemble the trip unit completely before calibrating theposition of the lever 129. For that reason, a removable flexible shield149 is disposed in an access opening 151 of the cover 79 in order toturn the calibrating screws 131 and 99. When the calibration is made,the shield 149 is replaced in the opening. The mechanism by which thereleasable arm 49 is released is shown in FIGS. 2, 4 and 6. Themechanism includes the trip bar 83, a trip lever- 153 and a latch lever155. A U-shaped mounting frame 157 is mounted on the base 81 with spacedupright sides 157a and 1S7b providing mounting support for the levers.The trip lever 153 includes a U-shaped portion 159 at the lower endwhich portion is mounted on a pivot pin 161 which extends from the side157a of the frame. The U-shaped lower portion of the lever maintains thelever upright adjacent the frame side 157a. The upper end of the triplever 153 includes a flange 163 which engages a notch 165 on the tripbar 83. As shown in FIG. 4 a portion of the trip bar extends through anopening 167 in the insuating base 79.

The latch lever 155 includes down-turned portions 155a and l55b whichare mounted on a pivot pin 169 the opposite ends of which are secured inthe sides 157a and 1S7b of the frame 157. A spring 171 is mounted on thepin 169 and has end portions engaging the levers 153 and 'l55for'biasingthe levers in the latched positions. 7

When the releasable arm49 is in the latched position as shown in FIG. 1,the arm which is pivoted on a pivot pin 173 is secured in thelatchedposition below the lever 155 and applies a rotatable forcethereon. The latch lever 155 is prevented from turning due toengagementof the lower end of the lever on a pin 175 which is mounted inthe U-shaped portion 159 of the trip lever 153. As a result of therotating force on the latch lever 155, the trip lever 153 is biasedclockwise and is prevented from movement by engagement of the flange 163in the notch 165 of the trip bar 83. When the trip bar is rotatedclockwise, the flange 163 is dislodged from the latch position withinthe notch 165 and the trip lever 153 rotates clockwise to move the pin175 from engagement with the lower end of the latched lever 155. As aresult the latch lever 155 is free to rotate about the pin I69 andthereby unlatch the releasable arm 49 from the latched position.

As shown in FIG. .3, a projection 177 extends from the upper comer ofthe trip bar portion 83a which projection is aligned with an aperture179 (FIG. 4) in-the housing base.79.,By extending a pin through theopening 179 (FIG. 2), and pressing against the projection 177, the tripbar may be tripped manually.

Another embodiment of the invention is that shown in FIGS. 7 and 8. Thisembodiment differs from a first embodiment in that the lever means ofthe first embodiment including the levers 119 and 129 are replaced inthe second embodiment by a single lever 181 which extends from the upperend to the lower end of the compartment as shown in FIG. 8. Inasmuch asonly the lever I81 differs from the previous embodiment, the remainingparts are identified with similar reference numbers.

More particularly, the lever 18] is pivotally mounted in a mannersimilar to the lever 129 in that it is provided with oppositely disposednotches which fit on corresponding projections 185 of the base 79 wherethe levers are retained in place by the cover 79. The lower end portionof the lever 181 is bifurcated to include spaced members 187 and 189(FIG. 7). The lever 181 is composed of magnetic material so that themembers 187 and 189 function as armatures which cooperate with themagnetic core which is disposed in the single inverted U-tumed portion69A of the conductor 69. In this embodiment, the U-shaped frame 107 ofthe previous embodiment including the flanges 109 is omitted.Accordingly, when an overload current of sufficient magnitude occurs inthe conductor 69, the mem bers 187 and 189 are attracted to the magneticcore 105, whereby the lower end of the lever contacts and rotates thetrip bar 83 clockwise thereby tripping the circuit breaker in the mannerdescribed above with respect to the first embodiment.

The lever 181 is similar to the lever means of the first embodiment inthat it is also provided with a calibration screw 131 which cooperateswith an armature adjusting knob 137 in the manner described.

Accordingly, the device of the present invention provides a new andnovel trip device for a circuit breaker which .is of a more compact sizethan the previous trip devices of the same rating. The advantage of thesmaller dimensions is due primarily to the use of lever means havingsmaller space requirements than magnetic tripping devices of priorconstruction. As a result of the more compact arrangement of parts theouter dimensions of the circuit breaker housing may also be reduced forcircuit breakers of the same rating.

What is claimed is: j l. A circuit interrrupter protective device forresponding to abnormal currents in the conductors of an electricaldistribution system and for actuating a circuit interrupter to open uponthe occurrence of predetermined operating conditions, comprising acircuit breaker having a first insulating housing, a cirucit breakermechanism with the housing and comprising separable contacts adapted tobe connected as part of the distribution system, the circuit breakermechanism comprising a releasable member movable from a latched positionto effect opening of the contacts, a latch lever movable between latchedand unlatched positions of the releasable member and being biased in thelatched position, a stationary magnetic structure for each conductor ofthe distribution system and comprising a coil and core assembly, anarmature, a trip bar movable to unlatch the latch lever and being biasedin the latched position, lever means associated'with each stationarymagnetiqsttructure for moving the trip bar to the unlatched position,the lever means comprising the armature and being movable in response toabnormal currents in at least one of the conductors, the lever meanscomprising a trip lever which is biased away from the core assembly,means for adjusting the spacing between the lever and core assembly anda bimetallic strip has one end mounted on the conductor and another enddisposed in a position adjacent to the trip bar to effect movement ofthe trip bar to the unlatched position.

2. The circuit interrupter protective device of claim 1 in which themagnetic structure, the trip bar, the lever means, and the spaceadjusting means are mounted within a second insulating housing, thesecond insulating housing being mounted within the first insulatinghousing, and in which mounting means are provided for the lever meansand comprise interfitting notch and prong members, one of th membersbeing on the second housing and the others of the members being on thelever means.

3. The circuit interrupter protective device of claim 2 in which thenotch members are in the trip lever and the prong members are in thesecond housing.

4. The circuit interrupter protective device of claim 3 in which thetrip lever is retained in place for pivotal movement by a cover on thesecond insulating housing.

5. The circuit interrupter protective device of claim 2 in which thesecond housing comprises a molded member of electrically insulatingmaterial and having molded notches therein, and the trip bar beingrotatably mounted in the notches.

6. The circuit interrupter protective device of claim 5 in which thesecond housing comprises a housing chamber divided into isolatedcompartments by spaced housing ribs, and the molded notches beingdisposed in the spaced ribs.

7. The circuit interrupter protective device of claim 2 in which thelever means comprise first and second levers, the first lever comprisingthe armature, the second lever comprises one of the notch and prongmembers and being engageable with the first lever to effect the spacingbetween the first lever and the core assembly.

8. The circuit interrupter protective device of claim 7 in which themeans for adjusting the spacing comprises an adjustable knob having'acam surface engaging the second lever to effect movement of the firstlever to the desired spacing.

9. The circuit interrupter protective device of claim 8 in which themeans for adjusting the spacing also comprises an indexing member havinga projection in one surface thereof, and the adjusting knob havingspaced notches for receiving the projection at various knob settings.

1. A circuit interrrupter protective device for responding to abnormalcurrents in the conductors of an electrical distribution system and foractuating a circuit interrupter to open upon the occurrence ofpredetermined operating conditions, comprising a circuit breaker havinga first insulating housing, a cirucit breaker mechanism with the housingand comprising separable contacts adapted to be connected as part of thedistribution system, the circuIt breaker mechanism comprising areleasable member movable from a latched position to effect opening ofthe contacts, a latch lever movable between latched and unlatchedpositions of the releasable member and being biased in the latchedposition, a stationary magnetic structure for each conductor of thedistribution system and comprising a coil and core assembly, anarmature, a trip bar movable to unlatch the latch lever and being biasedin the latched position, lever means associated with each stationarymagnetic sttructure for moving the trip bar to the unlatched position,the lever means comprising the armature and being movable in response toabnormal currents in at least one of the conductors, the lever meanscomprising a trip lever which is biased away from the core assembly,means for adjusting the spacing between the lever and core assembly anda bimetallic strip has one end mounted on the conductor and another enddisposed in a position adjacent to the trip bar to effect movement ofthe trip bar to the unlatched position.
 2. The circuit interrupterprotective device of claim 1 in which the magnetic structure, the tripbar, the lever means, and the space adjusting means are mounted within asecond insulating housing, the second insulating housing being mountedwithin the first insulating housing, and in which mounting means areprovided for the lever means and comprise interfitting notch and prongmembers, one of th members being on the second housing and the others ofthe members being on the lever means.
 3. The circuit interrupterprotective device of claim 2 in which the notch members are in the triplever and the prong members are in the second housing.
 4. The circuitinterrupter protective device of claim 3 in which the trip lever isretained in place for pivotal movement by a cover on the secondinsulating housing.
 5. The circuit interrupter protective device ofclaim 2 in which the second housing comprises a molded member ofelectrically insulating material and having molded notches therein, andthe trip bar being rotatably mounted in the notches.
 6. The circuitinterrupter protective device of claim 5 in which the second housingcomprises a housing chamber divided into isolated compartments by spacedhousing ribs, and the molded notches being disposed in the spaced ribs.7. The circuit interrupter protective device of claim 2 in which thelever means comprise first and second levers, the first lever comprisingthe armature, the second lever comprises one of the notch and prongmembers and being engageable with the first lever to effect the spacingbetween the first lever and the core assembly.
 8. The circuitinterrupter protective device of claim 7 in which the means foradjusting the spacing comprises an adjustable knob having a cam surfaceengaging the second lever to effect movement of the first lever to thedesired spacing.
 9. The circuit interrupter protective device of claim 8in which the means for adjusting the spacing also comprises an indexingmember having a projection in one surface thereof, and the adjustingknob having spaced notches for receiving the projection at various knobsettings.